Logistics eJournal最新文献

{"title":"When Variability Trumps Volatility: Optimal Control and Value of Reverse Logistics in Supply Chains with Multiple Flows of Product","authors":"Alexandar Angelus, Ö. Özer","doi":"10.2139/ssrn.3071398","DOIUrl":"https://doi.org/10.2139/ssrn.3071398","url":null,"abstract":"Problem definition: We study how to optimally control a multistage supply chain in which each location can initiate multiple flows of product, including the reverse flow of orders. We also quantify the resulting value generated by reverse logistics and identify the drivers of that value. Academic/practical relevance: Reverse logistics has been gaining recognition in practice and theory for helping companies better match supply with demand, and thus reduce costs in their supply chains. Nevertheless, there remains a lack of clarity in practice and the research literature regarding precisely what in reverse logistics is so important, exactly how reverse logistics creates value, and what the drivers of that value are. Methodology: We first formulate a multistage inventory model to jointly optimize ordering decisions pertaining to regular, reverse, and expedited flows of product in a logistics supply chain, where the physical transformation of the product is completed at the most upstream location. With multiple product flows, the feasible region for the problem acquires multidimensional boundaries that lead to the curse of dimensionality. Next, we extend our analysis to product-transforming supply chains, in which product transformation is allowed to occur at each location. In such a system, it becomes necessary to keep track of both the location and stage of completion of each unit of inventory; thus, the number of state and decision variables increases with the square of the number of locations. Results: To solve the reverse logistics problem in logistics supply chains, we develop a different solution method that allows us to reduce the dimensionality of the feasible region and identify the structure of the optimal policy. We refer to this policy as a nested echelon base stock policy, as decisions for different product flows are sequentially nested within each other. We show that this policy renders the model analytically and numerically tractable. Our results provide actionable policies for firms to jointly manage the three different product flows in their supply chains and allow us to arrive at insights regarding the main drivers of the value of reverse logistics. One of our key findings is that, when it comes to the value generated by reverse logistics, demand variability (i.e., demand uncertainty across periods) matters more than demand volatility (i.e., demand uncertainty within each period). To analyze product-transforming supply chains, we first identify a policy that provides a lower bound on the total cost. Then, we establish a special decomposition of the objective cost function that allows us to propose a novel heuristic policy. We find that the performance gap of our heuristic policy relative to the lower-bounding policy averages less than 5% across a range of parameters and supply chain lengths. Managerial implications: Researchers can build on our methodology to study more complex reverse logistics settings, as well as tackle other in","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130940012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Item Aggregation and Column Generation for Online-Retail Inventory Placement","authors":"Annie I. Chen, S. Graves","doi":"10.2139/ssrn.3464278","DOIUrl":"https://doi.org/10.2139/ssrn.3464278","url":null,"abstract":"Problem definition: This paper studies an online retailer’s problem of choosing fulfillment centers in which to place items. We formulate the problem as a mixed-integer program that models thousands or millions of items to be placed in dozens of fulfillment centers and shipped to dozens of customer regions. The objective is to minimize the sum of shipping and fixed costs over one planning period. Academic/practical relevance: A good placement plan can significantly reduce the operational cost, which is crucial for online-retail businesses because they often have a low profit margin. The placement problem can be difficult to solve with existing techniques or off-the-shelf software because of the large number of items and the fulfillment center fixed costs and capacity constraints. Methodology: We propose a large-scale optimization framework that aggregates items into clusters, solves the cluster-level problem with column generation, and disaggregates the solution into item-level placement plans. We develop an a priori bound on the optimality gap, and we also apply the framework to a numerical example that consists of 1,000,000 items. Results: The a priori bound provides insights on how to select the appropriate aggregation criteria. For the numerical example, our framework produces a near-optimal solution in a few hours, significantly outperforming a sequential placement heuristic that approximates the status quo. Managerial implications: Our study provides a computationally efficient approach for solving online-retail inventory placement as well as similar large-scale optimization problems in practice.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114988544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On Assortment Optimization with Endogenized Market Size","authors":"Ruxian Wang","doi":"10.2139/ssrn.3458757","DOIUrl":"https://doi.org/10.2139/ssrn.3458757","url":null,"abstract":"In this paper, we consider the joint effects of product substitution and endogenized market size. Under the substitution effects, a product's demand may be cannibalized by other substitutable products; while the market size, measured by the number of customers who are interested in one of the products from the same category, may be largely in uenced by the product offer set. We show that the \"loss-leader\" phenomenon may arise because of the endogenized market size: a product is sold at a price below its marginal cost, in order to stimulate other sales of more profitable products. We further establish the NP-hardness for the assortment problem under the joint effects and develop a fully polynomial-time approximation scheme.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"32 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115671434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of Blockchain Enabled Transparency in Risk Management and Sustainability of the Complex Global Supply Chains","authors":"Dr Pankaj Kumar Medhi","doi":"10.2139/ssrn.3448606","DOIUrl":"https://doi.org/10.2139/ssrn.3448606","url":null,"abstract":"Lack of transparency in the global supply chains has emerged as a major risk for sustainability in the recent times. This is due to customer awareness about human rights and environmental issues and government legislations in the hosting countries to hold the organizations responsible for the actions of their globally scattered suppliers. This has caused the globalization organizations to make their supply chains transparent. Blockchain technology has been proposed as an efficient solution to not only make supply chains transparent, but also bring unprecedented changes to processes related to global supply chains and bring sustainable competitiveness for the organizations using it. This work finds the issues of supply chains for which global supply chains are using blockchain and what operational benefits they are getting. We also discuss why it is the future of supply chain management.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130983058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Demystifying NDC","authors":"Lloyd Misquitta","doi":"10.2139/ssrn.3408587","DOIUrl":"https://doi.org/10.2139/ssrn.3408587","url":null,"abstract":"Since the 1960's the world’s travel industry has been dependent on the Global Distribution Systems (GDS) to price air-fares, aggregate content, combine airline schedules and availability into combinations accessible to travel agents. Over time, the accessibility was filtered to and other channels and this further grew into the aggregation of hotel and car content.<br><br>Digitisation enables airlines to excise more control over the content they want to display to the customer, un-bundle products and charging supplements for seats, bags, meals etc. Historically, the GDS has not offered the same level of control and flexibility and many airlines see New Distribution Capability (NDC) as an enabler to deliver better and richer content, although whether the end result proves to deliver a cheaper or better alternative to traditional GDS content remains unknown.<br><br>Subsequently, the legacy technology providers in the aviation ecosystem have commenced numerous forums to focus on what the ultimate dynamic pricing mechanism will showcase itself to be, however, there is still no definitive timeline determining the grasp in which airlines will move to a new formidable platform which is more accurate, robust and efficient. <br><br>There has been a transcendence with the emergence of the low cost carrier models, however, the plight to revolution against the distribution incapability comes at a price – inefficient revenue optimisation and a cascaded effect of air fares in the market.<br><br>This paper is not averse to adopting a new thought process and embracing new technology, but the intent is more inclined towards levitating the control and distribution back to the airline on how best to model its distribution capabilities and optimisation strategies and not be curtailed to one-dimensional eco-system where in orchestrated layers of convolution continues to exist, thereby derailing their propensity to optimise.<br>","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"22 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114023485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Potentialities of RFID-Based Traceability System in the Olives Post-Harvest Stage","authors":"Abderahman Rejeb","doi":"10.29226/TR1001.2019.94","DOIUrl":"https://doi.org/10.29226/TR1001.2019.94","url":null,"abstract":"Given that the major challenges for olive production and for producers are to improve fruit and oil quality, a plethora of analytical techniques are carried out for the purpose of traceability and validation of the authenticity of olive oil. However, due to many considerations, all of these methods remain only applied in the testing phase. Therefore, the olive oil supply chain actors have to cope with the new advancements in intelligent food logistics to address some traceability concerns. In this specific line of research, this paper aims to propose a theoretical framework for embedding RFID into the traceability system of olives in the post — harvest stage. Then, a discussion is centered on the potentialities of adopting RFID in this target process. RFID is a new emerging technology which opens up windows of opportunities for an effective and efficient traceability system design in the supply chain and logistics of a valuable commodity.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115242356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Centralized and Decentralized Warehouse Logistics Collaboration, Extended Version","authors":"Shiman Ding, Philip M. Kaminsky","doi":"10.2139/ssrn.3298228","DOIUrl":"https://doi.org/10.2139/ssrn.3298228","url":null,"abstract":"We bound the value of collaboration in a decentralized multi-supplier multi-retailer setting, where several suppliers ship to several retailers through a shared warehouse, and outbound trucks from the warehouse contain the products of multiple suppliers. \u0000 \u0000Academic/Practical relevance: In an emerging trend in the grocery industry, multiple suppliers and retailers share a warehouse to facilitate horizontal collaboration, in order to lower transportation costs and increase delivery frequencies. Thus far, these so-called Mixing and Consolidation Centers are operated in a decentralized manner, with little effort to coordinate shipments from multiple suppliers with shipments to multiple retailers. Facilitating collaboration in this setting would be challenging (both technically, and in terms of the level of trust that would be necessary), so it is useful to understand the potential gains of collaboration. \u0000 \u0000Methodology: We extend the classic one warehouse multi-retailer analysis of Roundy (1985) to incorporate multiple suppliers and per truck outbound transportation cost from the warehouse, and develop a cost lower bound on centralized operation as benchmark. We then analyze decentralized versions of the system, in which each retailer and each supplier maximizes his or her own utility in a variety of settings, and we analytically bound the ratio of the cost of decentralized to centralized operation, to bound the loss due to decentralization. \u0000 \u0000Results: We find analytical bounds on the performance of several decentralized policies. The best, a decentralized zero-inventory ordering policy, has a cost ratio when compared to a lower bound on the centralized policy of no more than 3⁄2 . In computational studies, we find that cost of decentralized policies are even closer to those of centralized policies. \u0000 \u0000Managerial implications: Easy-to-implement decentralized policies are efficient and effective in this setting, suggesting that centralization (and thus, a potentially complex and expensive coordination effort) is unlikely to result in significant benefits.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114679620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Logistics Capabilities on Mitigation of Supply Chain Uncertainty and Risk in Courier Firms in Pakistan","authors":"Syed Nasim Haider, D. Siddiqui","doi":"10.2139/ssrn.3285075","DOIUrl":"https://doi.org/10.2139/ssrn.3285075","url":null,"abstract":"Logistics capability is an essential capacity for transport and logistics firm to convey the value and services to the client. However, supply chain uncertainty and risk establish the obstacle while achieving operational excellence. The main objective of this research is to examine the impact of logistic capabilities on mitigating supply chain uncertainty and risk in courier firms in Pakistan. Research identified that operational flexibility, innovation and process optimization has a significant positive impact on company side risk and uncertainties whereas process optimization also positively impacted on customer’s side risk and uncertainties. An online survey was conducted and data were obtained from sample size of 150 employees from Pakistani logistics companies. We performed multiple regression analysis to indicate the impact of logistics capability in mitigation of supply chain uncertainty and risk.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128364196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Information Sharing and Strategic Supplier Partnership in Supply Chain Management: A Study on Pharmaceutical Companies of Pakistan","authors":"Ambreen Khan, D. Siddiqui","doi":"10.18034/ABR.V8I3.162","DOIUrl":"https://doi.org/10.18034/ABR.V8I3.162","url":null,"abstract":"The aim of this paper is to distinguish the relationship between different components of supply chain management (SCM) and its impact on the performance of pharmaceutical manufacturing firms in Pakistan. Data has been gathered from 35 pharmaceutical companies located in the big cities of Pakistan. Self-reported questionnaires were used to collect data from the managerial level people working in different pharmaceutical companies of Pakistan. The result indicates that strategic supplier partnership, level of information sharing and quality of information sharing significantly correlates with the performance of manufacturing pharmaceutical firms. The current study will prove fruitful for the organization in improving their performance by implementing concepts of SCM within their companies. The study explored that all independent variables significantly predicted the performance of the firm. Strategic supplier partnerships, quality of information sharing have a positive effect on the performance of pharmaceutical companies whereas the level of information sharing has a negative impact on performance. The findings provide the evidence for previous literature. Results are helpful to policy makers and management to integrate the concepts within the organization to increase the performance of the firm and to win competitive advantage.","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131729955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Managing Navigation Channel Traffic and Anchorage Area Utilization of a Container Port","authors":"Shuai Jia, Chung-Lun Li, Zhou Xu","doi":"10.1287/TRSC.2018.0879","DOIUrl":"https://doi.org/10.1287/TRSC.2018.0879","url":null,"abstract":"Navigation channels are fairways for vessels to travel in and out of the terminal basin of a container port. The capacity of a navigation channel is restricted by the number of traffic lanes and safety clearance of vessels, and the availability of a navigation channel is usually affected by tides. The limited capacity and availability of a navigation channel could lead to congestion in the terminal basin. When the navigation channels run out of capacity, the anchorage areas in the terminal basin could serve as a buffer. This paper aims to develop a mathematical model that simultaneously optimizes the navigation channel traffic and anchorage area utilization. We provide a mixed integer programming formulation of the problem, analyze its complexity, and propose a Lagrangian relaxation heuristic in which the relaxed problem is decomposed into two asymmetric assignment problems. Computational performance of the Lagrangian relaxation heuristic is tested on problem instances generated based on the operational data of a port in Shanghai. Computational results show that the proposed heuristic is able to achieve satisfactory performance within a reasonable computation time. Data files and the online appendix are available at https://doi.org/10.1287/trsc.2018.0879 .","PeriodicalId":243859,"journal":{"name":"Logistics eJournal","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122455879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}